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variational returns now the right raveled indices
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1 changed files with 15 additions and 9 deletions
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@ -12,7 +12,7 @@ from transformations import Logexp, Logistic
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class VariationalPrior(Parameterized):
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def __init__(self, name='latent space', **kw):
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super(VariationalPrior, self).__init__(name=name, **kw)
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def KL_divergence(self, variational_posterior):
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raise NotImplementedError, "override this for variational inference of latent space"
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@ -21,8 +21,8 @@ class VariationalPrior(Parameterized):
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updates the gradients for mean and variance **in place**
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"""
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raise NotImplementedError, "override this for variational inference of latent space"
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class NormalPrior(VariationalPrior):
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class NormalPrior(VariationalPrior):
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def KL_divergence(self, variational_posterior):
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var_mean = np.square(variational_posterior.mean).sum()
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var_S = (variational_posterior.variance - np.log(variational_posterior.variance)).sum()
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@ -40,7 +40,7 @@ class SpikeAndSlabPrior(VariationalPrior):
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self.pi = Param('pi', pi, Logistic(1e-10,1.-1e-10))
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self.variance = Param('variance',variance)
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self.add_parameters(self.pi)
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def KL_divergence(self, variational_posterior):
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mu = variational_posterior.mean
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S = variational_posterior.variance
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@ -49,7 +49,7 @@ class SpikeAndSlabPrior(VariationalPrior):
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var_S = (S - np.log(S))
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var_gamma = (gamma*np.log(gamma/self.pi)).sum()+((1-gamma)*np.log((1-gamma)/(1-self.pi))).sum()
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return var_gamma+ 0.5 * (gamma* (var_mean + var_S -1)).sum()
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def update_gradients_KL(self, variational_posterior):
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mu = variational_posterior.mean
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S = variational_posterior.variance
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@ -59,8 +59,6 @@ class SpikeAndSlabPrior(VariationalPrior):
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mu.gradient -= gamma*mu
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S.gradient -= (1. - (1. / (S))) * gamma /2.
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self.pi.gradient = (gamma/self.pi - (1.-gamma)/(1.-self.pi)).sum(axis=0)
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class VariationalPosterior(Parameterized):
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def __init__(self, means=None, variances=None, name=None, *a, **kw):
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@ -74,7 +72,15 @@ class VariationalPosterior(Parameterized):
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self.num_data, self.input_dim = self.mean.shape
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if self.has_uncertain_inputs():
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assert self.variance.shape == self.mean.shape, "need one variance per sample and dimenion"
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def _raveled_index(self):
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index = np.empty(dtype=int, shape=0)
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size = 0
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for p in self._parameters_:
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index = np.hstack((index, p._raveled_index()+size))
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size += p._realsize_ if hasattr(p, '_realsize_') else p.size
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return index
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def has_uncertain_inputs(self):
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return not self.variance is None
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@ -126,7 +132,7 @@ class SpikeAndSlabPosterior(VariationalPosterior):
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super(SpikeAndSlabPosterior, self).__init__(means, variances, name)
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self.gamma = Param("binary_prob",binary_prob, Logistic(1e-10,1.-1e-10))
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self.add_parameter(self.gamma)
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def __getitem__(self, s):
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if isinstance(s, (int, slice, tuple, list, np.ndarray)):
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import copy
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